Ultrastructural disposition of adriamycin-associated magnetic albumin microspheres in rats

The ultrastructural disposition of intra-arterially administered adriamycin-associated magnetic albumin microspheres has been investigated. The rat tail was used as the target organ and demarcated into the following three parts: T1, the injection site; T2, the target site; and T3, the posttarget site. Adriamycin HCl (2.0 mg/kg) was administered via the carrier through a cannula fixed at T1. The target site, T2, was exposed to a magnetic field of 8000 G for 30 min postdosing. Animals were sacrificed at scheduled time intervals over a 72-h period, and the tissue samples from T2 were observed by light and transmission electron microscopy. Electron microscopy revealed that microspheres traverse the vascular endothelium of the target tissue as early as 2 h after dosing. Gradual loss of tissue organization and cellular components, as a function of drug exposure time, demonstrated that the pharmacodynamic characteristics of the drug are not altered by its entrapment and delivery via the magnetic microspheres. The study confirms second-order drug targeting in the target tissue of healthy animals.

Factorial design based optimization of the formulation of albumin microspheres containing adriamycin

The use of factorial design in the formulation of adriamycin-associated albumin microspheres, using the heat-stabilization technique, is illustrated. The effect of stabilization temperature, protein concentration and stabilization time on the entrapment and recovery of adriamycin in microspheres have been investigated using a 2 x 4 x 4 factorial design. The associated drug content in unwashed and four times washed microspheres was determined using HPLC. Maximum drug association and drug recovery were obtained from microspheres synthesised using 25 per cent w/v albumin solution and stabilized at 120 degrees C for 2.5 min. Under these conditions, the entrapped and total associated drug content of the microspheres was about 4 per cent and 12 per cent w/w respectively, and the drug recovery was about 75 per cent. The in vitro dissolution study carried out using dynamic dialysis revealed that the release of adriamycin from these particles follows a bi-phasic pattern. The results demonstrate that use of short stabilization time, low protein concentration and low stabilization temperature are required for the formulation of microspheres with high adriamycin content.

Evaluation of drug delivery following the administration of magnetic albumin microspheres containing adriamycin to the rat

The disposition of adriamycin following its intra-arterial administration in rats as a solution (control) or via magnetic albumin microspheres (treatment group) has been investigated. The rat tail was demarcated into three segments: T1, the pre-target site; T2, the target site; and T3, the post-target site. In both groups, 2.0 mg/kg of adriamycin HCl was injected into the ventral caudal artery in T1 through a T-piece cannula. A magnetic field of 8000 G was directed towards T2. The concentration of adriamycin was measured in the heart, kidney, liver, lung, serum, small intestine, spleen, T1, T2, and T3 as a function of time using an ion-pairing HPLC assay. Areas under the mean adriamycin concentration-time curves were used to determine two indices of drug delivery: the relative tissue exposure and targeting efficiency. It was demonstrated that the magnetically responsive albumin microspheres altered the tissue distribution of adriamycin in rats. Administration of drug via magnetic microspheres was shown to increase the relative drug exposure to both T2 and liver.

Magnetically controlled targeted micro-carrier systems

Magnetically controlled targeted drug delivery systems are aimed at concentrating drugs at a defined target site, with the aid of a magnetic field. This technique has been developed specifically for directing drugs away from the reticuloendothelial system (RES). Literature on this topic suggests that these delivery systems are capable of altering the distribution of chemotherapeutic agents in the body. Hence these delivery devices offer the possibility of improving the therapeutic efficacy of the associated drugs. This paper reviews the work done to date towards the development and evaluation of biodegradable and non-biodegradable magnetic targeted drug delivery systems and outlines their future prospects and limitations in cancer chemotherapy.

Stability of morphine solutions in plastic syringes determined by reversed-phase ion-pair liquid chromatography

A reversed-phase ion-pair HPLC assay has been developed for quantitating morphine, codeine, apomorphine, and pseudomorphine in aqueous solutions. Using two types of plastic syringes, the effect of light (25 W) and temperature (22 and 3 degrees C) on the stability of morphine, over a 12-week period, has been investigated in the presence and absence of preservative and antioxidant. The leaching of contaminants from the plastic syringes to water stored in them, for a period of up to 12 weeks, has also been investigated. The results indicate that less than 3% of the morphine is degraded in both types of plastic syringes, stored in light at 22 +/- 2 degrees C. The degradation is even less prominent in the dark or at 3 degrees C. Pseudomorphine has been identified as the major degradation product. Using 5% degradation of drug as the criterion for the determination of the shelf-life of morphine, it was found that in one brand of plastic syringes, morphine has a shelf-life of the order of 20 and 33 weeks, in the absence and presence of preservative and antioxidant, respectively. In the other brand of plastic syringe, the drug has a shelf-life of greater than 1 year. Some unidentified leached contaminants have been detected in water stored in both brands of syringes.

Optimized synthesis of polyglutaraldehyde nanoparticles using central composite design

A central composite design was applied to the optimization of the synthesis of polyglutaraldehyde nanoparticles (PGNP). The effects of monomer concentration, surfactant concentration, pH, oxygen level, and stirring rate on the particle size, polydispersity, surface carboxyl group concentration, and yield of PGNP were investigated. The optimal conditions for the synthesis of PGNP were found to be: 7% (w/v) glutaraldehyde, 2.5% (w/v) dextran, pH 12, 70% (v/v) oxygen, and a stirring rate of 1080 rpm. Under these conditions, the values of the dependent variables adequately resembled those predicted by the model. The usefulness of these particles in the targeted delivery of cytotoxic drugs is discussed.

Optimization of high-performance liquid chromatographic analysis for isoxazolyl penicillins using factorial design

A 3 X 3 factorial design has been used to study the effects of pH and acetonitrile concentration of the eluents on the retention and resolution of cloxacillin, flucloxacillin and dicloxacillin on a C18 column. The logarithm of the capacity factors of these solutes have been found to vary linearly with the pH and quadratically with the acetonitrile content. The equations generated have been employed to predict experimental conditions necessary for an optimum separation. The chromatographic condition selected has been applied to the quantitation of flucloxacillin in human plasma using dicloxacillin as the interval standard. Sample preparation consists of protein precipitation and solid-phase extraction. The detection limit of the assay at 220 nm for flucloxacillin is in the region of 0.1 microgram/ml. This assay has been employed in a study of the relative bioavailability of two commercial flucloxacillin sodium capsules in ten healthy volunteers.

Quantitation of the release of doxorubicin from colloidal dosage forms using dynamic dialysis

The release of doxorubicin from submicrometer bovine serum albumin (BSA) microspheres has been quantitated using dynamic dialysis. Mathematical models have been proposed based on zero- or first-order release of drug from solid colloidal matrices. The models also account for the permeability constant of the dialysis membrane. Results obtained by the dynamic dialysis technique resemble those obtained using a conventional dissolution method. The release of doxorubicin from the microspheres can be adequately described by a biphasic zero-order model.

Analysis of p-aminobenzoic acid and its metabolites in urine and plasma by ion pair HPLC in the NBT-PABA pancreatic function test

An ion pair HPLC method which can simultaneously detect the major metabolites of an exocrine pancreatic function testing agent (NBT-PABA) in plasma and urine has been developed. This assay has been applied to a pharmacokinetic study of PABA and its metabolites in 3 healthy adult volunteers following the oral administration of 1 g NBT-PABA. The 6 h testing period currently used to collect urine following the NBT-PABA ingestion is adequate for the recovery of PABA and its metabolites. Plasma determination of these compounds may provide an improved evaluation of the pancreatic performance in patients with abnormal liver or kidney function.

Chromatography of progesterone and its major metabolites in rat plasma using microbore high-performance liquid chromatography columns with conventional injection and detection systems

A separation of progesterone and its metabolites 17 alpha-hydroxyprogesterone, 20 alpha-hydroxy-4-pregnen-3-one, androstenedione and testosterone by high-performance liquid chromatography with a ternary solvent system is demonstrated. It is found that using a 100 X 1 mm microbore column, higher sensitivity is obtained in the ultraviolet detection of these compounds by using conventionally sized flow cells despite the higher efficiency resulting from the use of a micro-flow cell. It is also shown that, when a non-eluting solvent is used for injection, large injection volumes do not reduce column efficiency, and a 14-fold increase in sensitivity is obtained with a 1-mm column in place of one 4.6 mm in diameter. Using solid-phase extraction and concentration of the sample as pretreatment, progesterone and its hydroxylated metabolites are determined in 0.5-ml samples of rat plasma. The progesterone levels are compared with those obtained by radioimmunoassay.

Determination of pharmacokinetics of cocaine in sheep by liquid chromatography

Cocaine was administered as 1-, 2-, and 4-mg/kg intravenous bolus doses to each of six sheep. Plasma samples were collected as a function of time and assayed for cocaine using reversed-phase ion-pair HPLC. The assay involved double extraction with ether and UV detection at 229 nm. Using 2 mL of plasma, levels of 1 ng/mL of cocaine can be measured. The concentration versus time data obtained for the plasma samples were analyzed by a "noncompartmental" method. The pharmacokinetic parameters of cocaine in sheep had mean values of 4.0 L/kg, 3.5 L/kg, and 0.29 L X min-1 X kg-1 for Vd, Vdss, and CL respectively. The clearance of cocaine in sheep was much higher than cardiac output. Pulmonary first-pass effect has been suggested as the possible explanation for the large clearance of cocaine in sheep.

Fasting and feeding variations of insulin requirements and insulin binding to erythrocytes at different times of the day in insulin dependent diabetics--assessed under the condition of glucose-controlled insulin infusion

Nine insulin-dependent diabetic patients were examined for insulin requirement, counterregulatory hormones, and receptor binding during their connection to glucose-controlled insulin infusion system. They were of 103% ideal body weight. A diet of 45% carbohydrate, 20% protein and 35% fat was divided into three meals and three snacks averaging the daily calorie intake of 1859 kcal. Following an equilibrating phase of 14 hours after the connection to the glucose-controlled insulin infusion system the blood samples were taken at 0800, 1200 and 1800. The insulin infusion rate increased at 0300 in the early morning from 0.128 mU/kg/min to 0.221 mU/kg/min (P less than 0.02). The postprandial insulin infusion rate jumped from 0.7 U/h (0700-0800) to 7.5 U/h (0800-0900). The calorie related and carbohydrate related insulin demands after breakfast were also highest and declined after lunch respectively (1.16 uU/kg/min kj vs. 0.61 uU/kg/min kj, P less than 0.05 and 236 mU/g CHO vs. 129 mU/g CHO and 143 mU/g CHO). Of the counterregulatory hormones the cortisol showed a significant diurnal rhythm to insulin demands. The insulin tracer binding was higher at 0800 before breakfast than that at 1200 before lunch (P less than 0.05). The increased binding could be better attributed to receptor concentration change than to affinity change. The cause of insulin relative insensitivity in the morning could be due to altered liver response to the cortisol peak in type 1 diabetics. The preserved variation of insulin binding in our patients might be referred to feeding.

Reversed-phase ion-pair high-performance liquid chromatography of adriamycin and adriamycinol in rat serum and tissues

An ion-pair reversed-phase high-performance liquid chromatographic method is presented for the determination of adriamycin and adriamycinol concentrations in rat serum and tissues. The scheme for developing the chromatographic conditions is discussed. A good separation of adriamycinol and adriamycin was obtained by using a high sodium lauryl sulphate concentration in the mobile phase. The retention times of adriamycinol, adriamycin and daunomycin (internal standard) were less than 3 min with no interfering peaks from endogenous constituents. A protein precipitation method was used to prepare the serum and tissue samples for injection.

Analysis of 5'-deoxy-5-fluorouridine and 5-fluorouracil in human plasma and urine by high-performance liquid chromatography

A relatively simple and sensitive high-performance liquid chromatographic (HPLC) method is described for measuring the two anticancer drugs 5'-deoxy-5-fluorouridine (5'dFUR) and 5-fluorouracil (5-FU) in human plasma and urine. The procedure for plasma includes solvent extraction using ethyl acetate-isopropyl alcohol (85:15) followed by silica gel column chromatography to separate these compounds from constituents normally occurring in plasma. The analysis by reversed-phase HPLC is performed on a phenyl column using an aqueous mobile phase with ultraviolet detection (280 nm). The overall recovery from plasma was 61% and 65% for 5'dFUR and 5-FU, respectively. The sensitivity limit of the assay for both compounds was 50 ng/ml of plasma. Analysis of these compounds in urine did not require the silica column chromatography isolation step.

The analysis of tricyclic antidepressant drugs at therapeutic blood levels by reversed-phase high-performance liquid chromatography using pairing and organic counter-ions

A serum assay method incorporating two internal standards suitable for routine clinical analysis of tricyclic antidepressant drugs at the therapeutic level is described. The method involves extraction and chromatography using a reversed-phase high-performance liquid chromatography system incorporating pairing and organic counter-ions. The quantitative characteristics of the method are reported and results are compared with consensus values for four commonly encountered drugs, amitriptyline, nortriptyline, imipramine and desipramine. The method is shown to be applicable to more recently developed antidepressants such as nomifensine and maprotiline and the flexibility of the chromatography is discussed. Sample chromatograms obtained from patient samples in the presence and absence of potentially interfering drugs and metabolites are discussed.

A chromatographic quality control procedure based on HPLC for 5-hydroxymethylfurfural in autoclaved D-glucose infusion fluids

A specific qualitative chromatographic assay method is described for 5-hydroxymethylfurfuraldehyde (5HMF) in degraded D-glucose solutions incorporating an internal standard. Comparison is made between the chromatographic method and the official direct ultraviolet absorption measurements at 284 nm for solutions of D-glucose degraded to different extents. Hospital samples of autoclaved Dextrose Injection, 5% w/v, are also examined by both methods and it is demonstrated that quite different results can be obtained depending upon the conditions of measurement. It is demonstrated that the direct absorption method does not provide an adequate limit test for compounds related to 5HMF.

Relative vasodilator potency of ATP, ADP, AMP and adenosine (Ado) in the cat hind limb

The relative vasodilator potencies of ATP, ADP, AMP and Ado were determined by bioassay using the skinned and unskinned cat hind limb and comparing the increase in blood flow induced by intra-arterial injection of the adenyl compounds. The relative vasodilator potencies of these agents were similar in either hind limb preparation and were as follows: ADP greater than ATP greater than Ado greater than or equal to AMP. ADP was 2-4 times more potent than ATP and about 200 times more potent than Ado or AMP. When the adenyl compounds were incubated in blood for 2 min before injection, their potencies were not changed in the bioassay. Furthermore, in a chemical assay, after Ado and ADP were incubated for 2 min in cat blood (at the concentrations used in the bioassay) only 3% of Ado and 29% of ADP were metabolized. The results indicate that ATP and ADP exert a vasodilator effect that is not dependent upon their conversion to Ado. This deduction cannot be made for AMP because its relative potency was quite similar to Ado. Since a similar relative potency was found in the skinned and the unskinned hind limb, it is concluded that the vasodilator effect due to ATP and ADP is occurring in skeletal muscle but this does not exclude simultaneous cutaneous vasodilation. The vasodilator effect of adenyl compounds may be related to purinergic receptor activation.

Predictive value of human placental lactogen determinations in pregnancy

The relation of human placental lactogen (hPL) levels to pregnancy outcome was studied in normal and preeclamptic pregnancies, hPL determinations were performed between 38 and 44 weeks of gestation, and the results were compared with birthweight and Apgar scores in three groups. The results of hPL determinations permitted prediction of intrauterine growth retardation in all except 2 patients. The value of hPL measurement as a screening test in pregnancy is noted.

Pregnancy complicated by heroin addiction

During a 5-year time span, 118 addicted women gave birth to viable infants. These patients were subject to an increased incidence of complicating medical problems as well as many obstetric problems leading to maternal or fetal risk. The obstetrician should be aware of the possibility of addiction and its effects on pregnancy, and when possible, appropriate management should be initiated. Intensive care of the neonate must be begun as soon as possible.

Renal carcinoma in pregnancy

A gravid patient presented with gross hematuria in the last trimester of pregnancy but did not permit diagnostic measures. After delivery a large abdominal mass, which proved to be renal cell carcinoma, was found. Previously reported cases are reviewed, and the importance of adequate workup of hematuria during pregnancy is emphasized.

Comparison of sterilization by tubal ligation and hysterectomy

A comparison was made between sterilization by hysterectomy and by tubal ligation at the time of cesarean section and as an interval procedure. All operations were done at one institution and, essentially, by the same physician population, allowing for promotion within the residency program. The major deterrent to hysterectomy was the associated high incidence of necessary blood transfusion. However, a hysterectomy does offer the benefits of a permanent and completely effective procedure and the removal of an organ which ultimately may be the source of other problems. If another pathologic condition exists, making ultimate hysterectomy likely, it is the procedure of choice for sterilization, avoiding risks, costs, and the inconvenience of another operation. Methods of elective sterilization must be individualized. If the patient is appraised of the increased risk of hysterectomy and desires this more definitive procedure on the basis of informed consent, the incidence of complications is not prohibitive. These should not deter the well trained surgeon but should mandate use of all available skills, intensive evaluation of the patient, and concerned recognition of the potential adverse consequences.

A diagnostic device for stress incontinence

Many methods of evaluating anatomic deformity of the urethrovesical angle are available. A new diagnostic device has been developed to determine the degree of rotation of the urethral axis, thus differentiating between type I and type II deformities causing stress incontinence. Preliminary study in 62 patients indicates that the instrument is accurate, simple, and easily interpreted. The device also has the advantage of being easily constructed, disposable, and inexpensive.